Prevention of foaming of hydrocarbon oils



Patented Feb. 25,1947

PREVENTION OF FOG F DROCARBON OILS Charles E. Trautman, Cheswick, and Henry A. Ambrose, lenn Township, Allegheny County, Pa, assignors to Gulf Research & Development Company, Pittsburgh, Pin, a

Delaware corporation oi No Drawing. Application November 5, 1945, Serial No. 626,898

. is Claims. (Cl. 252-491;)

This invention relates to the prevention of foaming of hydrocarbon oils, particularly mineral oils and lubricants containing them.

This application is a continuation-in-part of our co-pending application, Serial Number 478,154, filed on March 5, 1943, for Prevention of foaming of hydrocarbon oils.

Hydrocarbon oils and oil compositions containing them tend to foam or froth when agitated in the presence of gases or vapors, such as air, steam, oil vapor, products of combustion, and the like. The amount of foam or froth varies with the conditions under which the oil compositions are agitated, as well as the character of the composition. Under some conditions, the volume of foam or froth produced is many times that of the original oil, and even with mild agitation, substantial amounts of foam are produced in many oil compositions. In preparing and using such oils and oil compositions commercially, they are subjected to agitation under a wide range of conditions and frequently undesirable amounts of foam or froth are produced.

Various means of combating such foaming of oils and oil compositions have been proposed.

For instance, mechanical devices have been proposed for destroying or breaking foam as it is formed. Usually such devices have been cumbersome or inefilcient. or both, and they are not generally used commercially. Likewise, the incorporation of certain oil-soluble compounds in the oil has been proposed as a'means for preventing foaming; such compounds .being called "anti-foam agents. Unfortunately, no agent of this type has been found which is completely satlsfactory in commercial practice; and their effectiveness -sometimes diminishes rapidly in use or they must be added to the oil in such amounts that the desirable properties of the oil are impaired, or they are objectionable for other reasons.

Among the objects achieved by this invention is the provision of an improved method of 'preventing foaming of hydrocarbon oils, particularly mineral oils and oil compositions containing them, in which the normal foaming tendency of the oil is effectively abated or suppressed for long periods of use without deleteriously affecting the other properties of the oil.

Another object achieved by the present inventicn is the provision of new and improved antifoam agents and compositions capable of abating and inhibiting foaming of hydrocarbon oils and oil compositions when dispersed therein in minute amounts.

A further object achieved by the present invention is the provision of new and improved oil compositions, particularly improved mineral oils and lubricants, having marked resistance to foaming and other advantageous properties including resistance to emulsification and containing minute amounts of an oil-insoluble anti-foam agent finely dispersed therein.

We have discovered that foaming of hydrocarbon oils, particularly mineral oils and compositions containing them, can be efiectively suppressed or prevented without substantial modification of the desirable properties of such oilsby forming in the oil a. stable, fine dispersion of a small amount of a substantially oil-insoluble liquid condensation product of an organo-germanium oxide compound having a low interfacial tension toward the oil. We have found that bydrocarbon oil compositions containing such liquid organo-germanium oxide condensation products as a. stable, finely dispersed phase are markedly resistant to foaming even under the most violent conditions encountered in commercial practice. The presence of the finely dispersed insoluble liquid phase in the oil apparently causes the films of the oil foam to rupture, thereby quickly destroying the foam, In fact,

' particularly when an adequate amount of antifoam agent is used, its presence so rapidly breaks the oil foam that substantially all foam is destroyed as fast as it is formed.

The organo-germanium oxide condensation products contemplated for use according to this invention are composed primarily of a plurality of germanium atoms linked together through oxygen atoms, each germanium atom having attached to it at least one organic radical, and they may contain one or more other substituents. One particularly suitable class of these condensation products is the trimers of dialkyl substituted germanium oxide condensation products. These trimers are cyclic compounds in which germanium and oxygen alternate in a six membered ring and the germanium atoms are substituted with two alkyl radicals.

Typical organo-germanium oxide condensation products which have been found suitable for the purposes of our invention include, for example, the trimer of dimethylgermanium oxide and the trimer of diethylgermanium oxide. The oily liquid condensation products of diethylor dimethylgermanium oxide are particularly advantageous anti-foam agents for the present purposes because of their low solubility in hydrocarbon oils and low interfacial tension towards such oils.

' fective.

These compounds are generically represented by the following formula:

in which R represents a methyl or ethyl group.

For the purposes of the present invention we have found that the liquid organo-germanium oxide condensation products are particularly ef- These viscous oily liquids, in general, have low surface tensions and low interfacial tensions towards hydrocarbon oils. They also have low solubility in hydrocarbon oils and are readily dispersible in such oils, particularly mineral lubricating oils. In general, we flnd the condensation products containing simple organic radicals, such as the methyl, ethyl and short-chain alkyl groups, most advantageous for the purposes of our invention as they have quite low solubility in most hydrocarbon oils.

For the purpose of describing our invention in more detail hereinafter reference will be made particularly to the liquid condensation products of diethylgermanium oxide. It is to be understood, however, that this invention is not limited to the use of diethylgermanium oxide condensation products as anti-foam agents, but contemplates other organo-germanium oxide condensation products which are substantially insoluble in hydrocarbon oils and which exhibit low interfacial tension towards such oils.

We have found that the oily liquid condensation products of diethylgermanium oxide are particularly good anti-foam agents. Such conden sation products are readily formed from diethylgermanium oxide simply by heating the oxide to a temperature of at least about 120 C. Diethylgermanium oxide is a solid having a. melting point of about 175 C. However, upon heating, this compound readily forms a trimer having a melting point of about 19 C. which is liquid at ordinary room temperature. This trimer of diethylgermanlum oxide is a liquid substantially insoluble in the more viscous lubricating oils and readily dispersible therein, and it exhibits a low interfacial tension towards such oils. When introduced into these hydrocarbon oils in concentrations of 0.0005 to 0.5 per cent by weight, it effectively reduces the foaming tendencies of such oils. At the lower concentrations on the order of 0.001 per cent by weight, a small amount of foam may be formed. However, at concentrations of 0.01 per cent by weight and higher, substantially complete inhibition of foam formation is effected.

In preparing the dialkyl germanium oxides, such is diethylgermanium oxide, various methods may be used including the Grignard reaction. However, we have found it advantageous to proceed through the Frankland reagent which is more reactive. In carrying out the preparation of diethylgermanium oxide for example, tetraphenylgermanium is first prepared by reacting germanium tetrachloride with diphenylzinc. This reaction may be effected in benzene solution by heating to a temperature of 75 to 80 C. for relatively long time periods. After decomposing the excess diphenylzinc with sulfuric acid,

the tetraphenylgermanium may be recovered from the benzene solution. Diphenylgermanium dibromide can then be prepared from the tetraphenylgermanium by reaction with bromine.

vantageous.

This bromination is usually effected in two stages. In the first stage at room temperature one phenyl group is replaced-by bromine and in the second stage at a temperature of about 80 to C. a second phenyl group is replaced by bromine. The diphenylgermanium dibromide may then be reacted with ethyl magnesium bromide to form diphenyl-diethylgerman'ium, which upon bromine.- tion produces diethylgermanium dibromide. The diethylgermanium' dibromlde upon hydrolysis with aqueous alkali produces diethylgermanium oxide which is a solid having a melting point of 0.

As a class, these short-chain alkyl germanium oxide liquid condensation products are, for all practical purposes, substantially oil insoluble. They are also substantially insoluble in water and aqueous solutions. On the other hand, they can be readily dispersed in hydrocarbon oils to form stable dispersions containing extremely fine particles of oil insoluble liquid. In fact, we have prepared oil compositions containing such oil insoluble liquid alkyl germanium oxide condensation products dispersed therein in which the majority of the dispersed particles are on the order of one micron or less in size. Such fine dispersions of these condensation products in oils are stable and are markedly resistant to foaming. Oil compositions containing 0.01 to 0.5 per cent of these compounds finely dispersed therein yieldlittle or no foam when subjected to drastic foaming tests. In fact, compositions containing as low as 0.0005 per cent of a dispersed germanium oxide condensation product show a measurable resistance to foaming.

The liquid condensation products of diethylgermanium oxide described above are merely illustrative of this type of anti-foam agent, The liquid condensation products of other organogermanium oxides are also efiective in suppressing foaming of hydrocarbon oils and may be employed as the anti-foam agent. The amount used should be sufficiently in excess of the solubility of the compounds in the oil to give the required amount of dispersed liquid phase necessary to prevent foaming under service conditions. For this reason the liquid condensation products which are substantially oil insoluble are most ad- While we have found that the compounds containing the simple alkyl radicals, such as methyl and ethyl radicals, are especially advantageous for the present purposes, satisfactory results may also be obtained with organo-germam'um oxide condensation products containing other organic radicals provided that such organogermanium oxide condensation products are used in amounts in excess of their saturation solubility in the oils and further that they exhibit a low interfacial tension towards the oil.

The particle size of the insoluble liquid dis persed in the hydrocarbon oil has a marked effect on the resistance to foaming so imparted to the composition. In general, we have found that oil compositions containing dispersions of our new oil-insoluble anti-foam agents in which the liquid particles are about 2.0 microns and less in size are particularly advantageous for the present purposes. Such oil compositions are very stable in storage and. under service conditions, and they have a high resistance to foaming which they retain over long periods of use.

Further, since good resistance to foaming can be readily obtained with exceedingly smal1 proportions of our anti-foam agents finely dispersed in the hydrocarbon oils, the anti-foam agents of aniacao :1 it our invention do not deleteriously modify the other properties of such oils. Accordingly, the desired roam-resisting properties can be imparted to such oils without impairing their effectiveness as lubricants or for other intended uses.

In the commercial practice of this invention, ,oil compositions may be produced directhr in which the anti-foam agent is present in the desired small amount and fine dispersion. However, in certain embodiments of the invention. oil compositions initially containing relatively coarse dispersions and relatively high concentrations of the anti-foam agents may be first prepared and the desired finely dispersed agent concentration may be produced in the hydrocarbon oil during use by agitation thereof in the lubricating system, such as by gear pumps and other mechanisms. Such production of the desired fine dispersion in situ in the oil during use is sometimes advantageous. The amount of anti-foam agent and the fineness of the dispersion necessary to prevent foaming in a given case will vary somewhat with the particular oil and the agent employed as well as the service conditions to which the oil composition is subjected.

In preparing our oil compositions, the oil-insoluble anti-foam agent may be incorporated in the oil or oil composition by any suitable method capable of producing a stable fine dispersion of the liquid agent in the oil. For example, the anti-foam agent may be dissolved in a light hydrocarbon or other suitable solvent, such as mineral seal oil, gasoline, naphtha, hexane and benzene, and this solution may be introduced into the hydrocarbon oil to which it is desired to give anti-foam properties. The anti-foam agents of our invention are substantially soluble m these solvents at normal temperatures, and after such a solution has been formed it may be incorporated in the hydrocarbon oil or oil composition or crude oil simply by mixing and agitating the solution therewith. A fine dispersion of the anti-foam agent in the oil is thus obtained. A convenient solution for such use would contain at least 1.0 per cent of active antifoam agent. To add 0.01 per cent anti-foam agent to the final oil would require the addition of 1.0 per cent of the solution of anti-foam agent.

Where it is desired to form directly a dispersion of the anti-foam agent in the oil, various commercial colloid mills may be employed to disperse finely the liquid agent in the oil. In thi way, stable fine dispersions, in which the size of the dispersed liquid particles is within the range of 2.0 to 0.3 microns or,less, are readily obtained. Also, gear pumps may be employed to disperse the liquid anti-foam agent in the oil. The use of such gear pumps is advantageous in many embodiments of this invention, particularly those wherein fine dispersions of the antifoam agents are produced in situ in the oil. Other methods and apparatus may also be employed in dispersing these agents in oils or oil compositions.

It is sometimes advantageous to first disperse the liquid anti-foam agent in part of the oil and then add this concentrate dispersion to the remainder of the oil. Such concentrate dispersions can be readily prepared as stable uniform compositions. For instance, a mixture of oil and anti-foam agent in the desired proportionsm'ay be continuously circulated through a gear pump untfl a stable concentrate containing a uniform dispersion of the agent in the desired particle size is obtained. Thus, standardized concentrates can be prepared which can be added to lubricating compositions as needed. In such case, the desired amount of concentrate is added to the hydrocarbon oil composition, and the mixture is agitated until uniform. I

Also, such concentrates are themselves valuable anti-foam compositions. As they contain a preformed, dispersed, insoluble liquid phase of the desired particle size, they quickly break oil foams as well as suppress foaming in general. For instance, when added to oil or oil compositions which have foamed, they readily destroy the foam present and stop further foaming. In such cases, they can be quickly blended with oils, oil compositions, and crude oil and uniformly incorporated therein before serious foaming occurs.

For such purposes, oil concentrates containing at least 1.0 per cent of finely dispersed liquid organo-germanium oxide condensation products are advantageous. By adding from 0.5 to 50 per cent of such concentrates to mineral lubricating oils, improved lubricants having marked resistance to foaming are readily and easily obtained.

One particularly advantageous field of use for the anti-foam agents of our invention is in lubricants for internal combustion engines, such as automotive, aviation, Diesel and like engines, because we have found that even under the high temperature of operation of these engines, these compounds retain their foam-inhibiting properties. In lubricating such engines, appreciable foaming of the motor oil seriously interferes with effective lubrication. For instance, aviation oils (either straight or compounded oils) tend to foam at the low barometric pressures encountered at high altitudes. Also in lubricating such engines, particularly aviation engines, the lubricating oil is circulated under pressure through the parts to be lubricated. In doing so gear pumps are usually employed in supplying pressure oil to the engine and returning the oil from the engine sumps to the reservoir tank. In such systems, the scavenger pump is usually of such capacity as to maintain the engine sump in a substantially dry condition. With such dry sump systems, the scavenger pump frequently pumps large volumes of air with the oil, this air becoming dispersed in the oil. Under such conditions,

excessive foam often leads to loss of theoil from the engines and impairs the lubrication. By the present invention, such foaming can be readily overcome or suppressed. For example, an appropriate amount of our liquid anti-foam agents can be introduced into the circulating oil and dispersed therein by the gear pumps, or oil concentrates of theauti-foam agents can be intermittently injected into the oil and uniformly dispersed therein by such gear pumps Whenever substantial amounts of foam appear in the system. Further, such foaming can be prevented and the engine effectively lubricated at all times by employing an improved lubricant containing these liquid anti-foam agents dispersed therein from the beginning.

While our anti-foam agents and improved motor oils are particularly advantageous in lubricating engines wherein the oil is circulated under pressure by means of such gear pumps, they are also useful and advantageous in lubricating certain types of engines using splash lubrication. Also, modern Diesel engine oils usually contain relatively large amounts of additives of the detergent or detergent-dispersion type. It has been found that such additives .promote foaming. Ac-

cordingly, many Diesel oils foam badly. By the amaaoo vented and improved anti-foaming Diesel oils readily obtained. v

Another advantageous field of use is in gear lubricants, particularly for transmission gears of automotive equipment and the like. In lubricating such gears, the oil composition is violently agitated by the rotating gears and substantial amounts of foam are formed. This foam interferes with the lubrication and cooling of the gears. By the present invention, this foaming and its attendant difficulties in gear lubricants are effectively prevented and overcome.

Still another field of use for the products of our invention is in the light oils used in steam turbines. With these lightoils, agitation may produce considerable foaming. By the present invention, such foaming of light oils is effectively prevented. Furthermore, there is often a tend-v ency for steam turbine oils to emulsify with the water with which they are mixed. We have found that the anti-foam agents of our invention have an additional advantage in this use, because they generally increase the resistance of such oils to emulsification.

Our new anti-foam agents and compositions are also useful in other oil compositions and effectively prevent the foaming thereof. Indeed, they are useful and advantageous in any hydrocarbon oil or oil composition in which they are Substantially insoluble whether used as a lubricant or not, and in which it is desired to prevent foaming. However, they are particularly effective in combating foaming in mineral lubricating oils and lubricants.

The effectiveness of organo-germanium oxide condensation products of preventing foaming in different hydrocarbon oils and oil compositions may be demonstrated by means of the following foaming test in which the oil or oil composition is controllably aerated under fixed conditions so that the results obtained in a series of tests are directly comparable.

In carrying out this test, 200 cc. of the oil is placed in a tall graduate and air, in the form of fine bubbles, is passed upwardly through this column of oil at a controlled rate of 0.2 cubic feet per hour by means of a diffuser positioned in the bottom of the graduate. The graduate is closed with a suitable cover provided with air inlet and outlet tubes. The inlet tube extends to the bottom of the graduate and has a diifuser fixedly mounted on the lower end. Air is passed down through this tube and through the fine pores of the diffuser into the oil. uniform fine air bubbles are introduced at the In this way,

. 44 hours.

bottom of the oil column. The fine air bubbles pass up through the column of oil agitating it and forming foam. The volume of foam formed at the top of the oil column can be readily and accurately measured on the graduate.

By this test, the time to form a given amount of foam may be noted and recorded and the amount of foam formed in .a given time from the start of air flow through the oil may be measured and recorded. Either of these measurements gives a numerical value proportioned to the overall average rate of foaming. One or both of these values can be conveniently used to compare and evaluate the respective foaming properties of different oils and oil compositions.

In the above test, the foaming characteristics of the oil or oil composition tested are usually determined at room temperature under atmospheric pressure. However, if desired, similar foaming tests can be made at other temperatures and pressures as desired. For instance, foaming tests may be made at higher or lower temperatures by placing the graduate containing the oil in a thermostatically controlled bath maintained at the desired temperature. In fact, this is usually done even when the tests are made at room temperatures, the bath and oil in the graduate being brought to a standard temperature, usually 80-90" F., before aerating the oil. The foaming test may be made at reduced pressures by connecting the air outlet of the graduate to a suitable low pressure reservoir maintained at the pressure desired.

In the following specific examples. there are H- lustrated by means of this foaming test the advantageous results obtained by incorporating in a mineral lubricating oil the'organo-germanium oxide anti-foam agents of our invention.

Example In this example a liquid condensation product of diethylgermanium oxide was used as the antifoam agent, and it was incorporated in a highly refined parafilnic lubricating oil of S. A. E. grade. The diethylgermanium oxide condensation product was prepared according to the following procedure.

An ether solution of phenylmagnesium bromide was prepared by adding at room temperature an ethyl ether solution containing 170 grams of phenylbromide to 31.8 grams of metallic magnesium'covered with 400 mls. of ether. After reaction was complete, as evidenced by the disappearance of the magnesium, '75 grams of anhydrous zinc chloride was added to convert the phenylmagnesium bromide to diphenylzinc. 200 mls. of benzene was then added to the ether solution containing the diphenylzinc and the ether was driven off. 18 grams of germanium tetrachloride in 50 mls. of benzene was then added to the benzene solution containing the diphenylzinc. The mixture was then heated at 75 to 80 C. for This prolonged heating period effected reaction between the diphenylzinc and germanium tetrachloride to produce tetraphenylgermanium. The excess Frankland reagent formed from the phenylmagnesium bromide and zinc chloride (CaHsZnBr) was then decomposed by the addition of 450 mls. 2N sulfuric acid. The mixture maintained at a temperature of 50 to C. to prevent the tetraphenylgermanium from separating out was then poured into a separatory funnel. The bottom layer containing the zinc and magnesium salts was withdrawn and discarded. The top layer consisting of benzene and tetraphenylgermanium in solution was then collected. The benzene was then removed from the tetraphenylgermanium by heating the solution until all of the henzene was driven off. The tetraphenylgermanium was recrystallized from a minimum amount of gradually heating to a temperature of C. at The product from v 2 mm. of mercury pressure. this reaction was diphenylgermanium dibromide. It is believed that the tetraphenyl germanium was converted first at room temperature to triv phenylgermanium bromide and that. upon prolonged heating a second phenyl group was removed with the formation of diphenylgermanium dibromide. I

The diphenylgermanium dibromide was then mixed with an ether solution of ethyl magnesium bromide in excess of the stoichiometric amount to convert the diphenylgermanium dibromide to diethyl diphenylgermanlum. The mixture was then refluxed for 3 hours. The ether was then driven d and the residue heated to 110 C. for 3 hours. The ethylmagnesium bromide was then destroyed with 50 mls. of 2N sulfuric acid. The product was then extracted with ether. After removing most of the ether by evaporation, the residue was distilled at 1 mm. of mercury pressure and the fraction boiling at 120-130 C. at 1 mm. of mercury pressure was collected. This fraction consisted essentially of diethyl-diphenylgermanium. 4

The diethyl-diphenylgermanium from the previous step was dissolved in 28.5 mls. of ethylene bromide. 13 mls. of an ethylene bromide solution containing 0.7 gram of bromine per ml. of solution was added in successive portions. The mixture was-then heated at 90 to 100 C. for 15 hours to convert the diethyl-diphenylgermanium to diethylgermanium dibromide. After th prolonged heating period, the excess bromine and ethylene bromide and the phenyl bromide byproduct were removed by heating to a temperature of 150 C. The residue from this step was then distilled at 22 mm. of mercury pressure. 6.8 grams of liquid boiling at 90-95 C. was collected. This fraction contained the diethylgerrnanium dibromide.-

The diethylgermanium dibromlde from the above step was hydrolyzed by shaking it with about 50 mls. of a warm per cent. aqueous solution of sodium hydroxide. After the mixture was shaken well for a few minutes, 20 mls. of ethyl ether was added to extract the diethylgermanium oxide. The ether layer was separately collected and dried with anhydrous sodium sulfate. The dried solution was then heated to drive ed the ether and a residue of diethylgermanium oxide remained. The amount of diethylgermanium oxide recovered was 1.5 grams.

A diethylgermanium oxide condensation product was prepared from the above product by heating at a temperature of 175 C. This condensation product was liquid at room temperature.

Samples were prepared containing 0.001, 0.01, 0.1, and 0.5 per cent by weight, respectively, of the diethylgermanium oxide condensation prodnot. The condensation product had a low interfacial tension toward the selected oil and was practically insoluble although it was readily dispersible in the selected oil.

The lubricating properties of an improved nonioarning oil composition containing 0.01 per cent of anti-foam agent were substantially the same as those of the base oil, as shown by the inspection data in the following table:

Base oil plus Composition Base oil 0.01% antifoam agent Gravity, A. P. I 29.2 20.1 iscosi y, SUV at 100 F l. 181 1,175 0 F 101 101 Viscosity index 102 v103 Colo N. P. A 2% 2% Neutralization No 0. 02 0. 01

i To. compare the foaming properties of the base oil and the oil containing the diethylgermanium oxide compound, samples (200 cc.) of the oils were subjected to the above-described foam test at'ZB" F. The results were as follows:

As shown by the above test, this oil containing the anti-foam agent of our invention is effectively rendered non-foaming. The sample containing 0.001 per cent of the anti-foam a ent ,formed an appreciable amount of foam but showed a substantial improvement over the base oil. The sample containing 0.01 per cent of the anti-foam agent showed the formation of only a small amount of foam, while the samples containing 0.1 and 0.5 per cent of the anti-foam agent, respectively, showed no foam formation.

While our invention has been described above with reference to various specific examples and embodiments, it will be understood that the invention is not limited to such illustrated examples and embodiments and may be variously practiced within the scope of the claims herein made.

What we claim is:

1. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising producing in the oil a stable fine dispersion of a liquid organo-germanium oxide condensation product substantially insoluble in ,the oil and having a low interfacial tension toward the oil, in an amount suificient to decrease the normal foaming tendency of said oil and insomcient to deleteriously modify other desirable properties of the oil.

2. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising producing in the oil a stable fine dispersion of a liquid organo-germanium oxide condensation product substantially insoluble in the oil and having a low interfacial tension toward the oil, in an amount corresponding to at least 0.0005 per cent.

3. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising producing in the oil a stable fine dispersion of a liquid organo-germanium oxide condensation product substantially insoluble in the oil and having a low interfacial tension toward the oil, in an amount corresponding to 0.001 to 0.5 per cent.

4. A process of suppressing foaming in hydrocarbon oils and oil compositions containnig them, comprising producing in the oil a stable fine dispersion of a liquid organo-germanium oxide condensation product substantially insoluble in the oil and having a low interfacial tension toward the oil, in an amount corresponding to 0.001 to 0.5 per cent, said dispersion comprising predomi- 3 3? P rticles less than 2.0 microns in size.

2,41aseo 5. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising incorporating in said oil a solution of a liquid or'gano-germanium oxide condensation product having a low interfacial tension toward said oil in an amount suflicient to provide in the oil a greater amount of said condensation product than is soluble in said oil and producing a stable fine dispersion of said liquid organo-germanium oxide condensation product in said oil.

6. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising incorporating in said oil a suspension of a liquid organo-germanium oxide condensation product having a low interfacial tension toward said oil in an amount suflicient to provide in the oil a greater amount of said condensation product than is soluble in said oil and producing a stable fine dispersion of said liquid organo-germanium oxide condensation product in said oil,

7. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising producing in the oil a stable fine dispersion of a liquid alkyl-germanium oxide condensation product substantially insoluble in the oil and having low interfacial tension toward the oil in an amount sumcient to decrease the normal foaming properties of said oil and insufflcient to deleteriously modify other desirable properties of the oil.

8. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising producing in the oil a stable fine dispersion of a liquid dialkyl-germanium oxide condensation product substantially insoluble in the oil and having low interfacial tension toward the oil in anamount sufficient to decrease the normal foaming properties of said oil and insufficient to deleteriously modify other desirable properties of the oil.

9. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprising producing in the oil a stable fine dispersion of a liquid dimethylgermanium oxide condensation product substantially insoluble in the oil and having 'a low interfacial tension toward the oil in an amount sufficient to decrease the normal foaming properties of said oil and insuflicient to deleteriously modify other desirable properties of the oil.

10. A process of suppressing foaming in hydrocarbon oils and oil compositions containing them, comprisin producing in .the oil a stable fine dispersion ,of a liquid diethylgermanium oxide condensation product substantially insoluble in the oil and having a low interfacial tension toward the oil in an amount suflicient to decrease the normal foaming properties of said oil and insufficient to deleteriously modify other desirable properties of the oil.

11. A hydrocarbon oil composition substantially resistant to foam formation, comprising a 12. A hydrocarbon oil composition substantially resistant to foam formation, comprising a hydrocarbon oil and a liquid organo-germanium oxide condensation product substantially insoluble in said oil and having a low interfacial tension toward said'oil, stably dispersed in said oil in line particles in an amount corresponding to at least 0.0005 per cent of said oil.

13. A hydrocarbon oil composition substantially resistant to foam formation, comprising a hydrocarbon oil and a liquid alkyl-germanium' oxide condensation product substantially insoluble in said oil and having a lowinterfacial tension toward said oil, stably dispersed in said oil in fine particles in an amount corresponding to at least 0.001 per cent of said 011.

15. A hydrocarbon oil composition substantially resistant to foam formation, comprising a hydrocarbon oil and a liquid dialkyl-germanium oxide condensation product substantially insoluble in said oil and having a low interfacial tension toward said oil, stably dispersed in said oil in fine particles in an amount corresponding to at least 0.0005 per cent of said 011.

16. A hydrocarbon oil composition substantially resistant to foam formation, comprising a hydrocarbon oil and a liquid diamethylgermanium oxide condensation product substantially insoluble in said oil and having a low interfacial tension toward said oil, stably dispersed in said oil in fine particles in an amount corresponding to at least 0.0005 per cent of said oil.

17. A hydrocarbon oil composition substantially resistant to foam formation, comprising a hydrocarbon oil and a liquid diethylgermanium oxide condensation product substantially insoluble in said oil and having a low interfacial tension toward said oil, stably dispersed in said oil in fine particles in an amount corresponding to at least 0.0005 per cent of said 011.

18. A composition adapted to impart foam-resisting properties to hydrocarbon oils and compositions containing them when added thereto in an amount corresponding to 0.5 to 50 per cent, comprising a hydrocarbon oil having at least 1.0 per cent of a liquid organo-germanium oxide condensation product stably dispersed therein.

A CHARLES E. TRAUTMAN.

HENRY A. AMBROSE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Rosen Dec. 5, 1939 

